University of Laghouat
  • Laghouat, Algeria
Recent publications
This study focuses on a nonlinear viscoelastic wave equation involving logarithmic nonlinearity. It considers a nonlinear distributed delay influencing the boundary feedback, which is coupled with acoustic and fractional boundary conditions. Following the proof of global existence, we demonstrate the exponential growth and blow-up of solutions with positive initial energy under appropriate assumptions and for a general case of the kernel. This finding broadens and enhances earlier results. 2020 Mathematics Subject Classification. Primary: 93D20, 35L70; Secondary: 35B40, 76Exx.
For over four decades, the Inuleae tribe has been the focus of extensive research, initially centered on the morphological traits of its species to develop a comprehensive taxonomic classification. In recent years, molecular studies have further refined this classification, offering deeper insights into the phylogenetic relationships within the tribe. Currently, the Inuleae tribe comprises more than 600 species, organized into approximately 60 genera, distributed worldwide with a high degree of endemism. Investigations of the biochemical composition of these species have unveiled remarkable chemodiversity, particularly in their terpene and terpenoid profiles. These compounds have shown potent activities across a range of biological targets, including the neutralization of free radicals, antimicrobial effects, and anticancer properties. Additionally, they have shown significant anti-inflammatory effects, inhibited key enzymes related to other diseases, such as acetylcholinesterase and tyrosinase, and demonstrated strong efficacy against insect pests. This review provides a comprehensive analysis of the chemical diversity of terpenoids through characterization and typification, while also covering botanical aspects and bioactivity. Graphical abstract
A set of nitrogen-based heterocycles derived from the quinoline ring as well as cyclohexanedione and dimedone cores were subjected to in vitro anticancer activity evaluation against four different cancerous cell lines namely; HCT116, A549, PC3, and MCF-7 respectively to colon, lung, prostate, and breast cancers. Compound 3g presented promising results exhibiting the best IC50 values among the investigated compounds for the four tested cell lines. In vitro results were supported with in silico studies including molecular docking simulation in order to learn more about the binding mode of the studied derivatives with relevant drug targets in cancer treatment, namely; anaplastic lymphoma kinase and cyclin-dependent kinase 2. Compound 3g showing the best in vitro results exhibited the most promising docking scores among the studied compounds. Moreover, molecular dynamics simulation was performed to the best ligand studying its stability inside the selected enzymes. Furthermore, a DFT study was performed to investigate the structural composition, electron density, and reactivity of tested compounds to identify the most important parts of the derivatives and elaborate a structure–activity relationship.
Background Research into oxidative stress, cancer, and natural products revealed promising avenues for therapeutic intervention. Natural products are considered potent pharmaceuticals in combating oxidative stress and its relationship with cancer. Methods This study was carried out to evaluate the chemical profile and antioxidant activities using DPPH, ABTS, Phenanthroline, Cupric, Phosphomolybdenum, FRAP, Hydroxyl, Iron chelation in vitro assays, and anticancer properties by MTT method of Cistus creticus extracts. The chemical composition was determined using the LC/MS-MS technique. Therefore, in silico methods, particularly molecular docking and dynamic simulation were applied for molecular interaction analysis Results The obtained results revealed a wide variety of phenolic compounds in all studied fractions, in their qualitative and quantitative distribution. In most antioxidant assays, the butanol and ethyl acetate extracts exhibited the most effective effects, followed by the aqueous extract, while the petroleum ether and chloroform fractions exhibited much lower activity in comparison with standards. In parallel, ethyl acetate, n-butanol, and chloroform extracts exhibited potent antiproliferative activity against T47D and A549 cell lines, while the aqueous extract showed an IC50 in the range of mg/ml. Moreover, the analysis of interactions identified compounds against particular targets in studied cell lines using molecular docking showed a great affinity, especially for the ligands Hesperidin, Luteolin-7-O-glucoside and Rutin. Also, the molecular dynamic simulation of the interacting complexes Hesperidin-mTOR, Lutin-EGFR and Apigenin-HER2 revealed precise interaction, providing insights into their stability and dynamic behavior. Furthe Conclusion These findings confirmed the potential of Algerian Cistus creticus L. leaf extracts as promising therapeutic molecules for combating oxidative stress and cancer.
This study examines a wave equation within the framework of nonlinear viscoelasticity. Specifically, it considers a nonlinear, time‐varying delay feedback acting on the boundary, coupled with acoustic and fractional boundary conditions, and influenced by a logarithmic source term. Under suitable general assumptions on the kernel, we first establish the global existence of solutions and subsequently analyze their asymptotic behavior.
Teucrium polium L. is a plant with various claims of ethnobotanical use, primarily for inflammatory diseases. Chemical studies have already isolated different types of terpenes from the species, and studies have established its pharmacological potential. The present study evaluates the components of T. polium essential oil cultivated in the Algerian Saharan Atlas. GC-MS identified the major components as fenchone (31.25%), 3-carene (15.77%), cis-limonene oxide (9.77%), and myrcene (9.15%). In the in silico prediction, molecules with more than 1% abundance were selected. Regarding Lipinski’s rule, all molecules followed the rule. All molecules were found to be toxic in at least one model, with some molecules being non-genotoxic (6, 8, 10, 11, 12, 13) and others being non-mutagenic (5, 7, 9, 14). Three molecules were selected that showed the best results in pharmacokinetic and toxicity studies: the molecules that did not present carcinogenic potential (7—myrtenal; 9—myrtenol; 14—verbenol). The molecular target was established, and it seems that all three bound to the nuclear factor NF-kappa-B. Based on the docking and molecular dynamics results, these molecules have potential as anti-inflammatory and antitumor therapies, with further in vitro and in vivo studies needed to evaluate their activity and toxicity.
This paper introduces a novel single-loop control scheme for voltage regulation in islanded inverters, using a proportional-integral-lead (PI-Lead) controller designed within the synchronous reference frame (SRF) through a loop-shaping approach. Commonly, dual-loop controllers have been employed for this purpose owing to several limitations, such as insufficient stability with a narrow gain margin, a trade-off between stability and bandwidth, and constrained bandwidth due to the need for a significantly lower outer voltage loop bandwidth compared to the inner current one. The proposed method overcomes these challenges by integrating a Lead compensator, which enhances voltage regulation by eliminating steady-state error, improving stability margins, and providing a fast transient response while maintaining robustness against model parameter variations. Additionally, the control strategy reduces dependence on current measurements, except when dealing with inductive loads where virtual resistor-based active damping is necessary. Despite the challenges posed by multi-resonance phenomena and coupling effects inherent in single-loop SRF-based modeling, a comprehensive frequency-domain analysis is performed, with systematic controller parameter design guidelines to mitigate multi-gain crossover issues. Rigorous experimental results validate the theoretical findings and simulations, demonstrating the superior performance and practical effectiveness of the proposed control strategy compared to existing methods.
In this paper, we study a class of semilinear m(.)-Laplacian equations with variable exponent sources. By using the potential well method, we discuss this problem at three different initial energy levels. When the initial energy is sub-critical, we obtain the blow-up result and estimate the lower and upper bounds of the blow-up time. In the case of critical initial energy, we prove global existence, asymptotic behavior, and finite-time blow-up and determine the lower bound of the blow-up time. For super-critical initial energy, we establish the finite-time blow-up and estimate the lower and upper bounds of the blow-up time.
In this paper, a high-sensitivity biosensor for refractive index (RI) detection based on surface plasmon resonance (SPR) is proposed and analyzed. Based on the new D-shaped photonic crystal fiber (PCF). In the design, we chose gold on the polished part as the plasmonic material to improve the SPR effect. In addition, the numerical results were analyzed using the finite element method (FEM) for sensing applications. Accordingly, we measure RI at different wavelengths. The simulation results showed a high sensitivity of 12,300 nm/RIU in the RI range ranging from 1.27 to 1.41 and a maximum amplitude sensitivity AS of 1623.6 RIU⁻¹, with a sensing RI resolution of 8.13 × 10⁻⁶ RIU and a maximum figure of merit (FOM) of 560 RIU⁻¹. Due to the excellent parameters of the proposed sensor and the possibility of measuring larger RI ranges of the analyte, it is believed to be very useful in biomedicine and environmental sciences.
This research paper addresses a topic of interest to many researchers and engineers due to its effective applications in various industrial areas. It focuses on the thermoelastic laminated beam model with nonlinear structural damping, nonlinear time-varying delay, and microtemperature effects. Our primary goal is to establish the stability of the solution. To achieve this, and under suitable hypotheses, we demonstrate energy decay and construct a Lyapunov functional that leads to our results.
In this paper, we study the thermoelastic Timoshenko system with diffusion effect, memory, and distributed delay terms when they act on the second equation. Firstly, we use the Faedo–Galerkin method to show the well-posedness of the system. Then, we study the exponential stability using the Lyapunov functional. Next, we introduce a finite element scheme of the problem, and then we establish the discrete energy decay. Finally, we give a priori error estimates and some numerical simulations.
The enzyme activity of catechol oxidase (CO) give rise to enzymatic browning, leading to undesirable changes in fruits and vegetables. The aim of this work is to investigate the inhibitory effect of five essential oils (EOs) on CO from date fruits (Phoenix dactylifera). Catechol oxidase has been purified from date fruit through three-phase partitioning (TPP). Essential oils were extracts from Artemisia herba-alba, Artemisia campestris, Thymus vulgaris, Origanum vulgare, and Salvia Rosmarinus, and were tested against CO. The composition of these five essential oils was then identified using GC-MS. Major constituents identified were camphor (20.91%) and davanone D (19%) for A. herba alba, capillene (47.79%) for A. compestris, thymol (33.75%) and linalool (30.44%) for T. vulgaris, carvacrol (68.60%) for O. vulgare, and camphor (33.89%) for S. Rosmarinus. The EO from A. campestris was the most potent inhibitor of enzyme (IC50 = 3.44±0.09 mg/mL) while the weakest effect was observed for EO of O. vulgare (IC50 = 10.24±0.29 mg/mL). Different mechanism of inhibition was obtained. Hence, a competitive inhibition for both EOs of A. herba-alba and T. vulgaris, uncompetitive behavior for A. campestris, noncompetitive mechanism for S. rosmarinus and O. vulgare were observed. The docking molecular of those major constituents was investigated using crystal structure of CO from Ipomoea batatas (1BT1). The best-docked compound was davanone D (-5.55 kcal/mol) while camphor show weaker docking scores (3.79 kcal/mol). Thus, the results from our work could be important and offer an approach of control enzymatic browning using essential oils.
Self-compacting concrete improves fresh-state fluidity while maintaining mechanical properties, and presents an increasing research interest in fiber incorporation. However, the effects of fibers on rheological behavior and durability remain insufficiently studied in existing literature. This study provides new insights on the effect of polyester and steel fibers on the rheological, mechanical, durability, microstructural, and thermal properties of SCC. Nine different mixtures were studied: one reference SCC (without fibers), four SCC incorporating steel fibers, and four other mixtures incorporating polyester fibers. The four percentages studied for each fiber type were 0.25%, 0.5%, 0.75%, and 1%. The results showed that whatever their type, adding fibers reduces workability while improving compressive strength of SCC. Incorporating 1% of steel fibers increased flexural strength of SCC by 97%, whereas polyester fibers had no significant effect. In terms of durability, adding fibers increased SCC porosity but reduced its sorptivity. For instance, adding 1% of polyester fibers increased porosity by 9.5% whilst reducing sorptivity of SCC by 23% compared to the reference one. Polyester fibers also improved SCC thermal conductivity, whereas steel fibers had an inverse effect. An inverse proportionality between plastic viscosity and sorptivity was identified, highlighting the importance of plastic viscosity in influencing the transport properties of hardened SCC. Based on these findings, it is recommended that careful attention should be taken on the change of both rheological and transport properties when incorporating a given percentage of fibers into SCC.
Industrial equipment subjected to rigorous conditions of high speed and pressure leads to the development of cracks on metal surfaces. These cracks reduce the service life and threaten the safety of parts, and the deeper the crack, the greater the resulting damage. Crack detection and crack depth evaluation continue to take center stage in quantitative non‐destructive testing and evaluation (NDT&E 4.0). The accuracy of the rotating uniform eddy current (RUEC) probe in achieving fast and efficient detection of surface cracks is corroborated by a comparison with previous experimental results. Next, accurate crack depth classification is achieved by building deep learning model based on a sparse autoencoder (SAE) and a multi‐layer perceptron (MLP) model. These classifiers are combined with eddy current testing (ECT) data, including the normal magnetic component Bz. As a result, evaluation metrics such as accuracy increased by up to 100% with both precision and recall scores of 1 for the deep sparse autoencoder classifier compared to MLP performance. The originality of our approach is evident in the application of deep SAE, which achieves high classification accuracy. Furthermore, the integration of our high‐resolution NDT&E RUEC probe with advanced machine learning models for depth classification is both novel and impactful. This unique combination offers a comprehensive framework for crack analysis, from precise detection to detailed characterization. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.
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1,713 members
Djekidel Rabah
  • Department of Electrical Engineering
Makhloufi Zoubir
  • Engineering Department
Mohammed Belkheiri
  • Department of Electronics
Khedidja Benarous
  • Department of Biology
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Laghouat, Algeria
Head of institution
Phd.Benbertal Djamal